[...new Set(arr)];
var arr = [
  1,
  1,
  "true",
  "true",
  true,
  true,
  15,
  15,
  false,
  false,
  undefined,
  undefined,
  null,
  null,
  NaN,
  NaN,
  "NaN",
  0,
  0,
  "a",
  "a",
  {},
  {},
];

console.log([...new Set(arr)]);
